A known inspecting device that functions as a flow measuring device used to inspect a clean gas supplying device is described in JP Publication of Application No. 2015-12040 (Patent Document 1). More specifically, Patent Document 1 discloses an inspecting device (1) for inspecting the supplying state of inert gas supplied to any container (4) in an article storage facility including inert gas supplying portions (F) for supplying inert gas (an example of clean gas) to inside the containers (4) stored in storage sections (9). Each inert gas supplying portion (F) includes supply nozzles (53N) for injecting inert gas to inside a container (4) with the supply nozzles (53N) provided to a receiving support portion (15) for supporting a container (4) in a storage section (9). The inspecting device (1) includes inspection-purpose intake openings (1G) that come into contact with the supply nozzles (53N) when the inspecting device (1) is supported by the receiving support portion (15), flow meters (101), and inspection-purpose lines (103) each of which connects inspection-purpose intake openings (1G) to the corresponding flow meter (101). And when performing an inspection, with the receiving support portion (15) supporting the inspecting device (1) instead of a container (4), the flow rate of the inert gas that flows into the inspection-purpose lines (103) through the inspection-purpose intake openings (1G) from the supply nozzles (53N) is measured with the flow meters (101). This makes it possible to estimate the flow rate of inert gas supplied to inside a container (4) supported by the receiving support portion (15), based on the measured flow rate of the inert gas.
With the arrangement of Patent Document 1, when the inert gas is supplied to inside a container (4), the inert gas ejected from the supply nozzles (53N) flows to inside the container (4) through the intake openings (4G) with the intake openings (4G) provided to the container (4) in contact with the supply nozzles (53N) under the weight of the container (4). Therefore, the flow rate of the inert gas supplied to inside the container (4) can vary depending on how firm the contact is between the intake openings (4G) and the supply nozzles (53N) (that is, depending on the degree of air-tightness (to the exterior area) of the contact areas). In the arrangement of Patent Document 1, containers (4), each of which can hold a plurality of substrates, are used; thus, the total weight of a container (4) can change depending on the number of the substrates held in it. As the total weight of the container (4) changes, the firmness of the contact between the intake openings (4G) and the supply nozzles (53N) also changes. In light of this issue, in the arrangement of Patent Document 1, by providing inspecting device (1) with weight support portions each of which can support one or more weights for adjusting the total weight of the inspecting device (1), the firmness of the contact between the inspection-purpose intake openings (1G) and the supply nozzles (53N) can be adjusted by means of weights to match the firmness of the contact between the intake openings (4G) and the supply nozzles (53N) which changes depending on the state (i.e., the number) of the substrates held within a container (4). This makes it possible to obtain a flow rate of the inert gas measured by the flow meter (101) that has a value that is close to the flow rate of the inert gas actually supplied to inside a container (4) regardless of the number of substrates held in the container (4).